(1) Field of the Invention
The present invention relates to non-destructive testing and particularly to the display of the results of the examination of test objects with a beam of ultrasonic energy. More specifically, this invention relates to a computer controlled display which permits comparison of test results with preselected parameters commensurate with a selected examination range within the test object and/or with a threshold level. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
(2) Description of the Prior Art
This invention generally relates to the presentation of echo signals received from a workpiece being examined by means of a beam of ultrasonic energy. These echo signals are commonly converted to electrical signals and displayed on the screen of the cathode ray tube of an oscilloscope. The oscilloscope will include controls for varying the position and intensity of the electron beam of the CRT. However, prior art oscilloscope display devices have not had the capability of establishing, and subsequently displaying if desired, a "gate" or "window" commensurate with echo signals having at least a predetermined magnitude and/or received at a time commensurate with a reflection from a selected depth range within the body of the workpiece. Thus, it has previously been necessary to perform tedious measurements and calibrations in order to know, with precision, that a particular echo related signal being displayed has emanated from a point within the examination range of interest and/or is greater than a minimum predetermined amplitude